Electronic controllers are widely used in industrial automation and automotive applications, usually custom designed for specific groups of input sensors, output devices and control applications. Configurable Electronic Controllers (CEC), as described for example in WO 2005/029207 filed by Burkatovsky on Jul. 12, 2004 and WO 2006/008732 filed by Burkatovsky on Jul. 7, 2005 are considered particularly versatile, enabling design of electronic controllers capable of measuring a verity of digital and analogue sensors, as well as controlling a range of output devices such as motors, solenoids and indicators. US 2001/0039190 entitled “Configurable Electronic Controller” filed by Bhatnagar on Dec. 21, 2000, US 2001/0015918 entitled “Configurable Electronic Controller for Appliances” filed by Bhatnagar on Dec. 21, 2000, WO91/02300 entitled “Universal Analog Input” filed by Pascucci et al. on Jul. 12, 1990, U.S. Pat. No. 5,014,238 entitled “Universal Input/Output Device” filed by McLeish et al. on Nov. 28, 1989 and, technical brochures related to the SSP1492 sensor (Sensor Platforms Inc, California, U.S.A.) describe input circuitry in other devices based on or related to configurable electronics.
CEC devices use an input-cell to provide an electrical interface between the CEC and sensors connected to the device. One example of such a prior art input-cell is illustrated in FIG. 1, which shows, schematically, an embodiment of a prior art input-cell 240 as described and shown with reference to FIG. 4 of WO 2005/029207.
As is shown in FIG. 1, prior art input-cell 240 has an input pin 210 that is connected to a sensor (not shown). The sensor (not shown) provides a signal at a first input 236 of comparator 235. A synchronization voltage Vsync is received along synchronization input 255 from a CEC (not shown), and provided to a second input 238 of comparator 235 providing an output voltage Vcell to the CEC (not shown). Output voltage Vcell indicates which of first input 236 and second input 238 has greater amplitude. As is shown in FIG. 1, input-cell 240 has optional resistors 215 that are intended to bias the first input 236 of the comparator 235. Optional resistors 215 generally have a relatively high resistance value.
Input-cell 240 of FIG. 1 is of a type of input-cell that is particularly useful in measuring optical position sensors, analogue voltage output sensors and proximity sensors having specific output parameters. However, other sensors such as thermistors, magnetic Hall-Effect and integrated IC sensors (intended for pressure, acceleration and gas concentration) have different output parameters and require the use of a different type of input-cell to receive signals having the output parameters of the signals provided by such other sensors.
In prior art practice, it has been common to provide programmable controllers such as Allen Bradley Programmable Logic controllers with replaceable input-cells so that the user of the controller can select input-cells that are specially adapted to work with particular sensor types applied in a particular application. This solution however requires that the programmable logic controller be specially adapted to receive replaceable input-cells and further requires that a user have access to the exact input-cells that are required for a particular application. Such a solution also adds weight and cost the controller to support replaceable connections of the type necessary to allow interchangeability.
Further, there is a desire to provide CECs that do not require separate attachments so that a CEC that is flexible enough to perform a variety of tasks using a wide range of sensors can be provided in a single enclosure, that can be provided on a single substrate such as a printed circuit board or semiconductor pattern, or can be assembled, fabricated, manufactured or formed using common processes.
Thus, both for conventional Programmable Logic Controllers and CECs there is a need for an adaptive generic input-cell, which can serve a great number of different input sensors.